[Ground-station] channelized FM SDR

[Phil Karn]

On 10/31/20 11:10 AM, Douglas Quagliana wrote:
> Hi Phil,
>    Please let me know when the code is available. I would like to try
> getting it to run off an RTLSDR dongle and try to have it identify the
> callsigns of the repeaters that it receives. 
> 73,
> Douglas KA2UPW/5
>
In principle I could use the RTL-SDR, but I haven't actually used it
myself yet. It has a rather low dynamic range, so strong local repeaters
could blank weaker signals on other channels within its bandwidth.
Getting the most out it will probably require a lot of work on a good AGC.

My favorite SDR used to be the AMSAT-UK Funcube dongle, but it has a
very limited bandwidth (192 kHz). I'm now using the Airspy R2, which has
a 10 MHz bandwidth and 12-bit sampling. This is enough to easily cover
the entire 2m band. It can cover most of the 440-450 segment, but the
actual coverage of SDR is a little less than 10 MHz because of
anti-alias filtering ahead of the A/D. But it can easily cover the 5 MHz
half of whatever segment used in your local area for repeater outputs
(i.e., either 440-445 or 445-450).

Phil